Abstract The first highly pathogenic (HP) influenza A/H7N9 was reported in Guangdong in January 2017. To investigate the emergence and spread of HP A/H7N9 in Guangdong province, we sequenced 297 viruses (58 HP A/H7N9, 19 low pathogenic (LP) A/H7N9, and 220 A/H9N2) during 2016–2017. Our analysis showed that during the fifth wave, three A/H7N9 lineages were co-circulating in Guangdong: the local LP Pearl River Delta (PRD) lineage (13%), the newly imported LP Yangtze River Delta (YRD) lineage (23%), and the HP YRD lineage (64%). Previously circulating YRD-lineage LP during the third wave evolved to the YRD-lineage HP A/H7N9 in Guangdong. All YRD-lineage LP detected during the fifth wave most likely originated from newly imported viruses into Guangdong. Genotype comparison of HP A/H7N9 suggests limited outward spread of HP A/H7N9 to other provinces. The distribution of HP A/H7N9 cleavage site variants on live poultry markets differed from that found in humans, suggesting a V1-type cleavage site may facilitate human infections.

中文翻译：

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探索基因组流行病学在广东追踪高致病性甲型H7N9流感起源的效用

摘要 2017 年 1 月，广东报道了首例高致病性 (HP) 流感 A/H7N9。为了调查 HP A/H7N9 在广东省的出现和传播，我们对 297 种病毒（58 种 HP A/H7N9，19 种低致病性（ LP) A/H7N9 和 220 A/H9N2) 在 2016-2017 年期间。我们的分析表明，在第五波期间，广东有 3 个 A/H7N9 谱系共同传播：本地 LP 珠江三角洲 (PRD) 谱系 (13%)，新输入的 LP 长三角 (YRD) 谱系 (23%) ) 和 HP YRD 血统 (64%)。先前在第三波期间传播的长三角血统 LP 在广东演变为长三角血统 HP A/H7N9。在第五波中检测到的所有 YRD 谱系 LP 很可能来自新输入的广东病毒。HP A/H7N9 的基因型比较表明 HP A/H7N9 向其他省份的向外传播有限。